Cold pressure welding



July 14, 1959 w. DUBILIER cow PRESSURE WELDING Original Filed April 18, 1950 W/W WW nited States Patent assignments, to Kelsey-Hayes Company, Detroit, Mich.,

a corporation of Delaware Original application April 18, 1950, Serial No. 156,541. Divided and this application April 19, 1954, Serial No. 424,030

3 Claims. (Cl. 29--470.1)

This application is a division of my application Serial No. 156,541, filed April 18, 1950, entitled Arrangements for and Methods of Cold Welding, now abandoned.

The present invention relates to cold pressurewelding, i.e. the joining of metal members solely by pressure and without the addition of welding heat, in particular the welding of aluminum, copper and other metals or alloys capable of being cold pressure welded.

A method of welding together the contacting surfaces of two strips, plates, flanges or similar members of metal capable of being cold pressure welded has been proposed which comprises applying pressure to said members along a continuous line or upon a localized preferably rectangular area by means of suitable pressure tools or dies, to effect a percentage reduction in thickness of the two strips or the like members to be welded. Given a proper design of the shape and dimension of the welding dies and a proper control of the welding pressure to result in a predetermined percentage reduction of the total work thickness (about 70% in case of aluminum and 86% for copper), dependable and mechanically strong cold weld joints can be produced in a relatively simple manner by causing the metal sufiicien tly to flow at the contacting area or interface, in such a manner as to cause the metals of the adjoining surfaces to merge into a solid phase cold weld joint.

The cold pressure welding process as heretofore known has been practically limited to the making oflap joints connecting two superimposed relatively [flat members or parts, such as plates, strips, sheets, flanges or the like with the thickness of the overlapping portionsbeing indented or reduced by the welding tools or dies, in the manner pointed out.

An object of the present invention is the provision of a method of and means for producing a cold welded T- joint by butt welding the edge of a first work piece or member of coldpressure weldable metal, such as a plate, wire, etc. to the flatsurface of a plate or a similar work piece arranged at right angles to the former. l

The invention will be better understood from the following description of a few practical embodiments taken in reference to the accompanying drawing forming part of this specification and wherein:

Fig. 1 illustrates diagrammatically a basic arrangement for cold pressure welding together in a T-joint a pair of plates or the like in accordance with the principles of the invention;

Fig. 1A illustrates a modification of the arrangement of Fig. 1;

Fig. 2 is an enlarged cross-section of the joint obtained by means of a tool according to Fig. 1;

Fig. 3 is an isometric view of the joint according to Fig. 2;

Fig. 4 illustrates a method ofsecuring a separating disc in a tube according to the invention; and

Fig. 5 illustrates the joining of a closure disc to the 2,894,321 Patented July 14, 19 59 end of a metal tube by cold pressure welding according to the invention.

Like reference characters identify like parts in the different views of the drawing.

With the above object in view, the invention involves generally the supporting of a first plate or member with its clean butt end in contact with the surface of a second member to be connected thereto in a T-joint and the application to the members of sufficient welding pressure to cause both an indentation of the second member and an upsetting of the first member, to thereby produce an interfacial metal flow as a result of the combined indenting and upsetting actions conducive to joining of the menibers by a solid phase welding bond without the addition of any welding heat. By a proper design of the welding tools, the metal flow is restricted or diverted in the direction of the interface, to result in an intensified action at the interface and merging of the members into a solid phase welding bond with a minimum indentation or metal reduction being required.

Referring to Fig. 1 of the drawing, there is shown a first plate 10 and a second plate 11 to be welded thereto at right angle in a T-joint, both said plates consisting of metal capable of being cold pressure welded such as aluminum, copper, etc. Plate 11 is arranged at a right angle to and with its upper end abutting against the lower face of the plate 10, preparatory to the joining of the plates by cold pressure welding. For this purpose, plate 11 is held or gripped by a pair of anvils or jaws 12 and 13 with the edge of plate 11 arranged, in the example shown, flush with the upper faces of the anvils. The latter may constitute or form the jaws of a vise or similar clamping apparatus, sufiicient pressure being applied in the direction of the arrows a and b to firmly grip and prevent slippage of the plate 11 during the welding operation. The anvils 12 and 13 are provided with suitable recesses 12' and 13, respectively, at their inner ends adjacent to the edge of the plate 11.

The joining of the plates by cold welding is effected by means of a cooperating die 14 having a shoulder 15 and a projecting welding tip or tongue 16, said die forming part of a suitable press or equivalent device for applying pressure in the direction of the arrow c upon the upper face of plate 10 and in the direction of plate 11. As a result, an indentation 18, Fig. 2, in the plate 10 and compression orupsetting of the adjoining edge of member 11 will be caused, resulting in a metal flow in an outward or lateral direction along the interface. Given a proper design of the welding tip 16 and control ofthe welding pressure, the adjoining metals of both members will thus be caused to merge, as indicated by the flowlines 17 in Fig. 2, in sucha manner as to resultin an intimate solid phase cold weld joint between the members. The recesses 13' allow the metal displaced by the tip 16 and as a result of the upsettingaction to fiow laterally outwardly along the interface and to leave a projection or stiffening rib in the corner between the members upon completion of the welding operation.

As is understood, the shape and dimensions of the Welding tip 16 should be properly designed in relation to the thickness of the plates or other work pieces to be joined, both in order to cause a sufiicient cold flow of the metal at the interface and to result in a predetermined metal reduction orjdepth of the indentation 18. The latter is advantageously determined or controlled by the height of the tip 16 which acts as a stop or abutment for the die 14. In this manner, dependable and mechanically strong cold weld joints may be obtained. Alternatively, the depth of penetration of the tool 14 may be controlled by means of a stop associated with the press or other pressure applys ing means used.

- The adjoining surfaces of the plates and 11 to be welded should be sufliciently cleaned prior to the welding operation, preferably by scratch-brushing, to remove any oxide filmzpr' other'surface'contamination: liable to impede or prevent the attainment of an intimate and reliable oldi vveld'jointr In Fig. 1 the plate 11 is. shown arranged flush with the. upper surfaces of the"anvils-12 and 13- with the rec'esses 12 and 13' serving to allow the upset metal to flow laterally and along the interface, to result in a cold weld joint in the manner pointed out. According to a modified arrangement, the plate 11, as shown in Fig. 1A, may project slightly beyond the upper faces of the anvils 12 and 13; in which case the recesses 12' and 13' may be omitted, the metal again being upset and caused to flow laterally of the edge of the plate 11 and in the direction of the interfaceby the restricting action of the anvils 12 and 13. This arrangement is especially suitable in cases where theplate10 has a lesser thickness than plate,11 ,'whereby the reducing welding pressure prevents any distortion of the projecting edge of the plate other than the upset displacement or flow of the metal conducive to effecting the welding joint, in the manner described. g "For practical purposes, the tip 16 is advantageously fdesigned tohave a width about equal to the thickness of the plates being joined. If individual spot welds are made, their length is preferably a multiple of at least five times said width. Furthermore, the depth of the indentation18 01'' height of the welding tip 16 should be about 70% of the work thickness in the case of aluminum; to result in a mechanically strong and dependable Welding joint. For other metals a greater depth of the indentation will be required in accordance with the greater hardness of most cold weldable metals as compared with aluminum.

The depth of the. depression 18 required in a T-joint according to the invention 'is substantially less than where two members, such as plates, are connected in a lap joint with a single indentation made upon one of the members, as shown and described by U.S. Patent 2,522,408. .In ."the latter case it is necessary for the "single indenting tool'to penetrate through one of the members and into the other member, to cause an interfacial metal flow conducive to cold pressure welding of the members. 'In the case of the presentinvention, which amounts to a kind of combined lap and butt welding, the upset metal now of the hatred member or plate 11 assists or intensifies the flow caused by the indenting tool 16, to result in a combined interfa'cial metalfiow sufficient to effect weld- .ing'of 'the members with'a minimum depression of about 70% and without through 'penetration of the indented member.

Inthe arrangement according to Figs. '1 to -3, a continuous joint between the adjoining: surfaces of the plates 10 and 11 may "be effected by spacing the individual welds 18 *sufliciently close together sothat the eifective sealed area's ofany'two adjacent weldsmeet or overlap each other.

The individual weldingjoints as shown in Fig. 3'may be produced by eithero'ne or a'plurality'of reciprocating -tdols 14or by jmeaiis of one "or more pressure rollers :Jp'rovided with welding teeth and moved'in the direction bf the steam or line of Welds 18. Alternatively, a-rolle'r "with a continuous projection or circumferential tongue may'b'e" used in place of a tooth roller to produce a con- 'tinuous line Weld, as will be readily understood.

-4 shows an arrangement "for cold :wel'dinga separating Wall of disc 20 ina tube 21 by means or a' pair of circular 'anvils 22 and :23 fitting inside said tube and serving to hold 'said disc in' po'sition-and :a cooperating i welding'tool in th'e form of a roller-:24 haVlIIgi-al'PIOjECt- -irig"cireumferential-tonguets for applying weldingqpressure to the outside of the tube 21 opposite to'the ;edge of disc 20, in a manner readily understood from the foregoing. Tools. 22. and. 2.3. are. again. h fq tlfid. i h circumferential recesses 22 and 23' respectively, to allow the displaced metal to flow-laterally during the welding operation, to produce an eflicient and intimate cold weld joint, in the manner described hereinbefore. Alternatively, the roller 24- may be replaced by a plurality of radially slidable pressure applying tools or anvils having arc-shaped inner surfaces engaging the outside of the tube 21 and being provided with suitable welding tongues or teeth in a manner understood from the foregoing.

Fig. 4 shows a similar arrangement for cold Welding a closure disc fitting the inside end of a tube by means of a pair of gripping or positioning lanvils 28 and 30 and a welding tool 31 of any suitable design described hereinabove. In this case, the inner anvil 28 being suitable recessed at 28' engages the inner face of the disc 27, while anvil 30 engages both the outer face of said disc and the edge of tube 26. If desired, a further recess may be provided in the tool 30. The provision of a single recess 28' on the inner tube results in a smooth joint without a projecting-rib at or near the outside of the disc or closure 27.

In the foregoing, the invention has been described with specific reference to an illustrative device or method. It will be evident, however, that numerous modifications and variations, as well as the substitution of equivalent steps and elements for those shown and described herein, may be made without departing from the broader scope and spirit of the invention. The specification and claims are accordingly to be regarded in an illustrative rather than in a restrictive sense.

I claim:

1-. A method. of joining in .a T-butt' joint a pair of elongated ductile cold pressure weldable metal members comprising producing a butt end at right angle to the plane of a first member to be joined to a second member, providingthe areas of contact of said members to be joined with uncontaminated metallic surfaces, arranging said first member with its butt end in surface-to-surface contact with a .planar surface of said second member, supporting the :portion of said first :member inwardly of the free end .portionthereof adjacent to said second member against distortion, and applying, without the addition of-external welding heat, to a localized area of said second member having a cross-sectional dimension of the order of the thickness of said second member and oppesite to the end of said first member a. pressure, to cause an indentation of said second member and to indent and laterally upset the adjoining end of said Efirst member, thereby to produce and divert a metal flow of said first member in the direction of the initial interface of said .members such as to create an intense interfacial action between said members by the combined upsetting and indenting actions conducive to joining said members in a .solid phase cold welding bond at ttheiinterface thereof.

2. A method of joining -.in a Tabutt joint ,a pair of ductile cold pressure -weldable metal plates comprising producing a butt end surface at right angle to the plane of a first vplate .to be joined to asecond plate, providing theareas of contact of said plates to be joined with uncontaminated metallic surfaces, arranging .saidjfirstjplate with its endsurface in contact with a'planar surface of said secondplate, supporting the portion of said'first plate upsetting randiindenting lactionsconducine .tojjoining' said plates in a solid phase cold welding bond at said area.

3. A method of joining in a T-butt joint a pair of ductile cold pressure weldable metal plates comprising producing a butt end surface at right angle to the plane of a first plate to be joined to a second plate, providing the areas of contact of said plates to be joined With uncontaminated metallic surfaces, arranging said first plate with its end surface in contact with a planar surface of said second plate, supporting the portion of said first plate inwardly of the free end portion thereof adjacent to said second plate against distortion, and applying, without the addition of external Welding heat, to a line of localized spaced rectangular welding areas of said second plate having a width of the order of the thickness thereof and opposite and parallel to the end surface of said first plate a pressure, to cause indentations of said second plate and 15 2,707,824

to indent and laterally upset the adjoining end of said first plate, thereby to produce and divert a metal flow of said first plate in the direction of the initial interface of said plates such as to create an intense interfacial action between said plates by the cornbined upsetting and indenting actions conducive to joining said plates in a plurality of solid phase cold welding joints at said areas.

References Cited in the file of this patent UNITED STATES PATENTS 2,264,897 Becker et a1 Dec. 2, 1941 2,522,408 Sowter Sept. 12, 1950 2,608,887 Sowter Sept. 2, 1952 Sowter May 10, 1955 

